Sure some people in even colder area will chime in shortly, but I've used bubble-wrap around banana trunks after watching some folks do that in Kentucky and Tennessee to preserve some growth, and have thought about trying that for some other stuff where trunk/root survival is paramount. We primarily use the frost cloth out here (along with people emergency-draping their stuff in sheets when a freeze is about to hit).
How tall is the tree? If it's less than 6' tall: I've protected mangos and some other stuff their first year out here by hammering a couple of 6' stakes from HD's garden department in around the tree and using either frost cloth or plastic painting drop "cloth" (just the big sheets of plastic from the paint department trimmed with scissors) stapled to the stakes. Plastic might need to be vented during the day if the tree is completely covered though (otherwise it creates ideal conditions for fungus), porous frost cloth doesn't. Ideally you don't want this kind of insulation touching the parts of the tree you want to insulate if it's frosting out.
We also dump a bunch of tree mulch on the root area going into winter to add some additional insulation to the roots (edit: but that said, we have winters that are on the dry side; ymmv in terms of mulching the base when it's wet/snowing out)
The tree is small, I have a 3 ft. Avocado, then some other rootstock that I'm grafting onto (which will stay in pots through next year and I can bring inside if cold). I use the clear painters plastic as a poor mans greenhouse for my winter carrots, so I guess I could just throw that over top, and maybe then even throw another blanket on top. I guess it sounds like most people just use what they have around and make it work. I just have some bacon rootstock avocado's that I know will freeze before the Mexicola graft, so I figured the trunk is the most important, and saw that silver pipe insulation which is padded and looks waterproof, so I wasn't sure if there is a problem with "wrapping the trunk", like if it helped spread disease or something, or if I can just wrap that up pretty high through the winter, even if it's only in the 40's, I didn't know if there was a problem with essentially leaving that as a full winter accessory, even on warm days, or if it eventually becomes a problem over time. My hope is obviously to have trees that are too big to cover, but I guess you have to deal w/current problems before future ones!
Topic: Cold weather insulation on trees (Read 1071 times)